128 
development of beneficial tia ieee and in preventing 
the accumulations of organic acids in the soil, which is often the 
chemical factors of soil fertility atrolled 
by the gardener than are the physical. If the plants are to 
rg 
gardener who would deny the plants the very small amount of 
material which is derived from the soi 
e greatest factor i in the rapid eaaik of leafy parts is an 
Pp 
Ss 
however, the most available form of plant food which we can 
use, and because it is so soluble must be applied in very small 
amounts at times when growth is going on 
Stahl h 1 
i per ton oF aitogen 
her sl availabl form. WI i at the 
rate of twenty to thirty tons per acre each year, it wall eee as 
muc as can possibly be used by the crops of vegetables 
However, nitrate of soda may be used in small amounts to speed 
up the vegetables in a cold season, or to re increased yields of 
th plants, which, like cabbage and lettuce, the leaves or 
stems are the desired parts. hen the seeds or fruits are used 
it is necessary t e a considerable amount of phosphoric 
acid, and as this is deficient in stable manure, and is usually in 
s quantities in sandy garden soils, the stable manure should 
be reinforced e addition of enough acid phosphate to make 
the annual application at least eight hundred pounds per acre 
The presence of plen hosphoric acid in soil insures the 
ruits. 
round bone is one of the most valuable sources of phosphoric 
acid, but is somewhat slowly available, and should be used only 
for those plants like asparagus or rhubarb, which remain several 
years in one piece of groun 
